So Bristol Blue and Cobalt are basically the same thing? But if the pigment range is greenish blue to dark blue, does that include deep purple blue or should I be looking for something else to call it?

It was still interesting to me as I thought ALL Bristol Blue glass was old...............for some reason I thought they had stopped production of THE actual "Bristol Blue".

The technical stuff about the colour and content of the glass is also interesting but a little hard to apply without a chemistry set and perhaps a scanning electron microscope??

By the way...........I bought 2 pieces of REAL Chance glass today and I didn't even need to email you to check............all your training is paying off..............now hurry up with the book so we can all be millionaires!